A slurry is passed through a filter cloth 0.02 m² in area at a constant rate, with 4 x 10^–5 m³/s of filtrate being collected. After 100 s, the pressure is 4 x 10⁴ N/m²; after 500 s, it is 1.2 x 10⁵ N/m². The same filter-cloth material will be used in a plate-and-frame filter press having an area of 0.5 m², which can hold a cake of thickness, L, of 0.04 m, and which will process the same slurry. Assume the filtration will be at a constant rate, and then at a constant pressure after the pressure reaches 8 x 10⁴ N/m². If the volume of cake per volume of filtrate is 0.02, calculate the time required to fill the filter frame.